Conventionally, there are widely used various types of digital audio apparatuses capable of recording or playing audio data. For example, a HD drive being an apparatus capable of playing CD (compact disc) is widely used, and also a disc medium to and from which audio data can be written and read, such as a mini disc (MD) for example and a recorder/player compatible with such a disc medium are in widespread use.
In the systems such as the MD drive and CD drive, audio data is managed per so-called “program”. In the following description, “program” will refer to a group of data recorded under management as one unit in a disc. In the case of audio data for example, one piece of music is equivalent to the “program”. It should be noted that a piece of music is generally called one “track” and so a “program” will also be called “track” in the following description.
Recently, it has been proposed to use a hard disc (HD) drive for writing and reading the above audio data. The currently available hard disc has a considerably large capacity as compared to the disc media such as an MD for example, and thus can store a far larger volume of data as music signals than the MD and the like.
The above leads to thinking it up to build a digital audio system having integrated therein a CD drive, MD drive and a hard disc drive.
Such a system may be adapted to record or “dub” audio data read from a CD for example to an MD or hard disc or to dub audio data recorded in a hard disc to an MD.
Data recorded in a medium such as a CD, MD or the like is managed per track. The recorded-data management per track is effected based on a TOC (table of contents) recorded in a recording area different from a one in which audio data is recorded, in both the CD and MD.
Assume here that audio data read from a CD or MD as a dubbing source is dubbed to a hard disc and multiple continuous tracks recorded in a disc as the dubbing source are recorded by one dubbing operation.
In this case, a stream of audio data for the multiple tracks will be transferred to a hard disc drive and written to a hard disc in the drive.
It will be more user-friendly to manage multiple tracks of audio data thus dubbed to the hard disc per track as in the CD or MD than to manage the audio data as one track (file).
Description will be made of dubbing of audio data to an MD for example. In this case, a certain method is used to detect a breakpoint of each piece of music in a stream of the audio data, and the TOC is updated at each time taking the detected breakpoint as those of the music piece. Thus, the dubbed audio data is managed per track. More specifically, it is assumed that input digital audio data is in compliance with a CD format for example and there exists sub Q data as sub-code data. In this case, the continuity of the sub Q data within the track unit is monitored and a data position where the continuity is lost is registered as a breakpoint of the track in the TOC. Alternatively, a no-sound interval longer than a predetermined length of time in the audio data is registered as a breakpoint of the track. As it is well known, the sub Q data inserted in digital audio data in the CD format includes time indication indicative of a play time of each track, and discontinuity of the time information can be regarded as a track breakpoint.
However, some digital audio data have no sub-code data inserted therein. In this case, the detection of a track breakpoint depending upon the existence of the sub Q data is impossible. In this case, however, it suffices to detect a no-sound interval longer than the predetermined length of time. Even when a digital audio data is divided in two tracks in the TOC for example, the sound in one track is continuos to that in the other track in some cases. On the contrary, even one track has a no-sound interval long enough to be determined as a track breakpoint as the case may be. Therefore, it is difficult to accurately determine a track breakpoint depending upon the detection of a no-sound interval.
The above programs take place also in dubbing an audio source read from a CD or MD for example to a hard disc (HD). More specifically, it is assumed for example that dubbing is made to a hard disc to enhance the recording efficiency in the above-mentioned dubbing system. In this case, to always record a digital audio data having undergone audio compression, the less reliable no-sound interval detection has to be adopted since the audio-compressed data does not include any sub-code information as in the CD format.
With the conventional method of track delimiting for dubbing by detecting a track breakpoint from the state of an audio data stream and generating management information based on the result of detection, it is difficult to always determine a track breakpoint with a high accuracy for management of the audio data.